Field of the Invention
The present invention relates to inguinal hernia repair, and more particularly to an inguinal hernia prosthetic having lateral non-encircling cord locating structure which is configured to constitute the physiologic structure prior to the hernia defect.
Background Information
Hernias have plagued humans throughout recorded history, and descriptions of hernia reduction date back to Hammurabi of Babylon and early Egyptian writings.
Inguinal hernias are generally described as protrusions of abdominal cavity contents through the inguinal canal. The inguinal canal is a passage in the anterior abdominal wall which conveys the spermatic cord, in men, and the round ligament, in women. The inguinal canal is larger and more prominent in men. The spermatic cord is the cord-like structure in males formed by the vas deferens and surrounding tissue (including nerves and testicular blood supply) that run from the abdomen down to each testicle.
Inguinal hernias are very common. It has been estimated that 5% of the population will develop an abdominal wall hernia at some time in their lifetime. The repair of inguinal hernias is one of the most frequently performed surgical operations. There are two types of inguinal hernias, direct and indirect. Direct inguinal hernias occur when abdominal contents extend through a weak point in the fascia of the abdominal wall and into the inguinal canal. Indirect inguinal hernias occur when abdominal contents protrude through the deep inguinal ring.
Most patients with inguinal hernias elect surgery to repair inguinal hernias and avoid the possibility of a strangulated hernia. The procedure to repair a hernia involves, basically, pushing the piece of intestine back into place and surgically repairing the abdominal wall so the intestine cannot push through again. Hernia surgery, called herniorrhaphy or hernioplasty, can be an open procedure or a laparoscopic procedure.
Original hernia surgery utilized the patients existing tissue to repair the defect and this is now known as “pure tissue” repair of a hernia defect. Edwardo Bassini in 1888 posted a milestone in the history of not only hernia surgery, but of all surgery, when he reported a reduction in the recurrence rate to about 10% (from a conservative estimated 30-40% rate earlier) with his operation which was a unique combination of understanding of anatomy and application of surgical thinking and technique. This 10% recurrence rate was achieved at a period without antibiotics, primitive anesthesia and at a time when patients often suffered with their hernia until they reached a giant size before submitting to surgery.
Bassini's operation epitomized the essential steps for an ideal tissue repair. He opened the external oblique aponeurosis through the external ring, then resected the cremasteric fascia to expose the spermatic cord. He then divided the canal's posterior wall to expose the preperitoneal space and did a high dissection and ligation of the peritoneal sac in the iliac fossa. Bassini then reconstructed the canal's posterior wall in three layers. He approximated the medial tissues, including the internal oblique muscle, transversus abdominus muscle and transversalis fascia to the shelving edge of the inguinal ligament with interrupted sutures. He then placed the cord against that newly constructed wall and closed the external oblique aponeurosis over it, thereby restoring the step-down effect of the canal and reforming the external inguinal ring.
For well over a century, Bassini's pure tissue repair procedures, with several modifications (e.g. Halsted, McVay, Tanner, Shouldice . . . ) have helped preserve useful life in hundreds of thousands cases. While most modern “herniologists” view pure tissue repair as a method to be discarded, its very economical cost structure makes it, even today, the commonest form of hernia repair in most part of the developing world.
Hernia repair prosthetics have been developed, also called hernia patches and hernia meshes, for use in what is known as a tension free repair of a hernia defect. The prosthetic generally bridges the gap forming the defect and the patient's tissue is not “stretched” over the defect, thus allowing the tissue to remain “tension free”. The tension-free mesh repair is invariably linked to Lichtenstein whose work and progress over two decades culminated in the tension free Lichtenstein repair. The “tension free” prosthetic hernia repair procedures have evidenced a significant reduction in reoccurrence of hernias over the pure tissue repair, an minimized recovery period, and a decrease in post operative patient pain and have thus become the most popular repair for hernia defects.
Numerous surgically implantable hernia repair prosthetics have been proposed, such a polypropylene mesh patches for the repair of inguinal, and other abdominal wall, hernias. These prosthetics are generally intended for permanent placement within a patient's body space.
U.S. Pat. No. 5,593,441 is a representative example of one hernia prosthesis and discloses ventral hernia and/or chest wall reconstruction prosthesis that is a polypropylene mesh covered with an adhesion resistant barrier, such as a sheet of expanded PTFE. In the repair of ventral hernias and in chest wall reconstruction, the composite is positioned with the barrier relative to the region of potential adhesion, such as the abdominal viscera.
International Publication No. WO 97/35533 proposed a universal composite prosthesis in which one side of a layer of mesh material is completely covered with a layer of barrier material. The mesh material promotes biological tissue in-growth while the barrier material retards biological tissue adherence thereto.
U.S. Pat. No. 2,671,444 to Pease discloses a non-metallic mesh surgical insert for hernia repair. The non-metallic mesh surgical insert is preferably made from a polyethylene mesh.
Inguinal hernias are commonly repaired using a sheet of mesh fabric, such as polypropylene or PTFE (polytetraflouroethylene), which may be trimmed, as necessary, to match the particular size and shape of the inguinal floor. A slit, or keyhole, is preformed or made by the surgeon from the lateral end of the mesh opposite the medial corner of the inguinal canal toward the medial end of the mesh to form a pair of lateral tails that are separated to receive the spermatic cord there between. The tails may then be overlapped to encircle the cord and reinforce the internal ring.
U.S. Pat. No. 5,716,409 discloses an inguinal hernia repair sheet for use in surgery that includes an opening to receive a spermatic cord and a passageway designed to allow the opening to fit around the spermatic cord.
U.S. Pat. No. 4,769,038 discloses a plug for the repair of a femoral hernia. The plug or prosthesis has multiple layers or panels and fits around the spermatic cord.
PCT Application No. WO 96/14805 discloses a double layer prosthesis that is applied to a patient with an inguinal hernia. See also U.S. Pat. No. 5,813,975 for an example of a keyhole type inguinal hernia mesh.
European Patent No. 0719527A1 discloses dual layer prosthesis for an indirect inguinal hernia. The first layer is a solid sheet while the second layer has a center hole and a strip cut towards the center hole.
U.S. published patent application No. 2001-0049538 is a set of plugs and hernia mesh pieces for a particular surgical technique.
U.S. Pat. No. 6,174,320 discloses a suture-less hernia repair patch having a slit for receiving a patient's chord structure when placing a patch in a patient for hernia repair.
U.S. published patent application 2005-0192600 discloses a suture-less, tension free, one-piece, double layer, inguinal hernia repair prosthetic is preferably formed of a single piece or sheet of repair fabric, such as polypropylene mesh, PTFE mesh, biologic material, or combinations thereof. The prosthetic sheet preferably includes a fold line dividing the sheet into two general halves. Each prosthetic half of the prosthetic sheet is preferably shaped generally to fit within the inguinal canal. Each prosthetic half of the sheet includes an opening in the inner portion of the sheet and a slit extending to the peripheral portion of the prosthetic half. The slits extend to generally opposite side of the prosthetic. Each opening is adapted to receive a patient's spermatic cord structure there through.
U.S. published patent application 2004-0068275 discloses a complex hernia prosthetic. This reinforcement comprises a first piece and a second piece which are assembled with one another, said first piece comprising a longitudinal edge of corrugated shape, level with which said second piece is fixed. In this reinforcement, said first piece comprises a cutout forming a zone, located at a distance from said longitudinal edge, for the spermatic cord to pass through it, and comprises a flap which is joined to it and is dimensioned so as to extend close to said longitudinal edge and to broadly cover the zone of said first piece extending between said longitudinal edge and said passage zone, this flap being raised in relation to said first piece in order to engage the spermatic cord between said first piece and itself and being foldable against said first piece in order to hold this cord between this first piece and itself.
U.S. Pat. No. 6,565,580 discloses an inguinal hernia correcting prosthesis having an upper layer and a lower layer connected to each other by a flexible band, the flexible band having a first end fixed to the upper layer next to a recess provided on an edge of the upper layer, and a second end fixed next to a hole provided in the lower layer and connected by a cut to an external edge of the lower layer, the hole being axially aligned with the band and the recess.
U.S. Pat. Nos. 7,154,804 and 6,497,650 disclose prosthesis for repairing a tissue or muscle wall defect. The prosthesis comprises a layer of repair fabric having first and second and an edge that extends between the first and second surfaces. The prosthesis also includes a barrier that is inhibits the formation of adhesions with adjacent tissues and organs. The barrier may overlap a portion of the first and second surfaces. The barrier may be formed separate from and attached to the layer of repair fabric to permanently cover a portion of the edge. The repair fabric may be formed from a material which is susceptible to the formation of adhesions with sensitive tissue and organs. The cord protector may be formed from material which inhibits the formation of adhesions with sensitive tissue and organs. The barrier may overlie a portion of at least one of the first and second surfaces of the repair fabric.
These U.S. Patents and published patent applications are incorporated herein by reference in their entirety. Some of these earlier hernia repair prosthetics are complex. Several use a plug or a locating member to fit within the hernia defect itself. When considering the hernia defect as a defect in the muscle, the problems with contemporary plug or patch prosthesis are easier to highlight. In both situations of using conventional patch prosthesis or plug hernia prosthesis (somewhat less common) the “hernia defect” is conventionally considered as “cured” with the application of the hernia prosthesis as the hernia defect is covered or filled. However in both situations of using conventional patch prosthesis or plug hernia prosthesis the “muscle defect” is left untouched. The “defect” remains, but the hernia is prevented through the prosthetic. In fact with plug type repairs the “muscle defect” is actually increased as the plug expands the muscle defect in filling the hole. Consequently in this sense these existing prosthetics fail to reconstruct the pre-hernia physiology.
Although these medical advances are acknowledged for their usefulness and success in reducing the incidence of reoccurrence of the hernia, there remains a need or needs for more improvements in the surgical repair of inguinal hernias, and in attempts to reconstitute the pre-hernia physiology. Further, there is a need for an improved implantable inguinal hernia repair prosthetic having structure to facilitate the repair and to protect the cord structures, namely the spermatic cord, from damage.